Showing papers by "Laval University published in 1992"

Effect of captopril on mortality and morbidity in patients with left ventricular dysfunction after myocardial infarction. results of the survival and ventricular enlargement trial

Abstract: Background. Left ventricular dilatation and dysfunction after myocardial infarction are major predictors of death. In experimental and clinical studies, long-term therapy with the angiotensin-converting—enzyme inhibitor captopril attenuated ventricular dilatation and remodeling. We investigated whether captopril could reduce morbidity and mortality in patients with left ventricular dysfunction after a myocardial infarction. Methods. Within 3 to 16 days after myocardial infarction, 2231 patients with ejection fractions of 40 percent or less but without overt heart failure or symptoms of myocardial ischemia were randomly assigned to receive double-blind treatment with either placebo (1116 patients) or captopril (1115 patients) and were followed for an average of 42 months. Results. Mortality from all causes was significantly reduced in the captopril group (228 deaths, or 20 percent) as compared with the placebo group (275 deaths, or 25 percent); the reduction in risk was 19 percent (95 percent conf...

A second-generation linkage map of the human genome.

Abstract: A linkage map of the human genome has been constructed based on the segregation analysis of 814 newly characterized polymorphic loci containing short tracts of (C-A)n repeats in a panel of DNAs from eight large families. Statistical linkage analysis placed 813 of the markers into 23 linkage groups corresponding to the 22 autosomes and the X chromosome; 605 show a heterozygosity above 0.7 and 553 could be ordered with odds ratios above 1,000:1. The distance spanned corresponds to ∼90% of the estimated length of the human genome.

Specific amplification of 18S fungal ribosomal genes from vesicular-arbuscular endomycorrhizal fungi colonizing roots.

Abstract: The first DNA sequences obtained from arbuscular endomycorrhizal fungi are reported. They were obtained by directly sequencing overlapping amplified fragments of the nuclear genes coding for the small subunit rRNA. These sequences were used to develop a polymerase chain reaction primer (VANS1) that enables the specific amplification of a portion of the vesicular-arbuscular endomycorrhizal fungus small subunit rRNA directly from a mixture of plant and fungal tissues. The specificity of this primer for arbuscular endomycorrhizal fungi was demonstrated by testing it on a number of organisms and by sequencing the fragment amplified from colonized leek (Allium porum) roots. This approach, coupled with other molecular techniques, will facilitate rapid detection, identification, and possibly quantitation of arbuscular endomycorrhizal fungi.

Visceral Obesity in Men: Associations With Glucose Tolerance, Plasma Insulin, and Lipoprotein Levels

Abstract: The relations of regional adipose tissue (AT) distribution measured by computed tomography (CT) to plasma insulin-glucose homeostasis and lipoprotein-lipid levels were studied in 58 obese and 29 lean control men. In the group of obese men, the visceral AT area measured by CT was positively correlated with fasting plasma triglyceride and insulin levels and with glucose and insulin areas under the curves measured during a 75-g oral glucose tolerance test. Visceral AT area was also negatively associated with plasma high-density lipoprotein (HDL) and HDL2 cholesterol levels. The relative accumulation of abdominal fat, estimated by the ratio of abdominal to femoral AT areas obtained by CT, was also a significant correlate of indices of carbohydrate metabolism and was the best univariate correlate of plasma lipoprotein levels. No significant associations were observed between the visceral AT area, the ratio of abdominal to femoral AT areas, and indices of carbohydrate and lipoprotein metabolism in the group of lean men. On the other hand, the subcutaneous abdominal AT area was a significant correlate of the glucose area under the curve in both groups of men, but this association was not independent from the percentage of total body fat. No relationship was observed between the femoral AT area and indices of carbohydrate metabolism in either lean or obese groups. In obese men, however, the femoral AT area was negatively correlated with plasma triglyceride concentration and positively correlated with plasma HDL and HDL2 cholesterol levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Efferent connections of the centromedian and parafascicular thalamic nuclei in the squirrel monkey: a PHA-L study of subcortical projections.

Abstract: The subcortical projections of the centromedian (CM) and the parafascicular (Pf) thalamic nuclei were examined in the squirrel monkey (Saimiri sciureus) by using the lectin Phaseolus vulgaris-leucoagglutinin (PHA-L) as an anterograde tracer. Both CM and Pf project massively to the striatum where they arborize in a complementary fashion. On the one hand, CM innervates most of the putamen caudal to the anterior commissure, a dorsolateral rim of the putamen rostral to the anterior commissure, discrete areas of the head of the caudate nucleus close to the internal capsule, and a lateral sector of the body of the caudate nucleus. On the other hand, Pf provides a heavy input to the head, body, and tail of the caudate nucleus, and to the rostral putamen, excluding the areas innervated by CM. In addition, Pf projects more discretely to the nucleus accumbens and the olfactory tubercle. Therefore, the projections from both CM and Pf cover the entire striatum, with those from CM arborizing into the "sensorimotor" striatal territory and the ones from Pf innervating the "associative-limbic" striatal territory. Furthermore, CM and Pf project to extrastriatal subcortical structures, such as the globus pallidus, the subthalamic nucleus, and the substantia nigra, where they also terminate in a complementary fashion. Topographically and cytologically, Pf is closely related to the subparafascicular nucleus (sPf). The Pf-sPf complex projects to the hypothalamus, the substantia innominata, the peripeduncular nucleus, and the amygdala. It also gives rise to descending efferents arborizing in various brainstem structures, including the inferior olivary complex. Additional studies with retrograde double-labeling methods show that distinct cell groups within CM project to the motor cortex and the striatum. Likewise, separate neuronal populations within the CM-Pf-sPf complex give rise to striatal and brainstem projections, the former arising from CM and Pf and the latter mainly from sPf. The complementary nature of CM and Pf projections to the striatum and other basal ganglia components suggests that this thalamic complex participates in a highly ordered manner in the parallel processing of the information that flows through the basal ganglia.

Predictors of smoking behaviour: an application of Ajzen's theory of planned behaviour.

Abstract: The aim of the present paper was to verify the basic assumptions underlying the theory of planned behaviour for the prediction of cigarette smoking intentions and behaviour among adults of the general population (study 1) and a group of pregnant women (study 2). Each study was developed based upon Ajzen's theory of planned behaviour. In both studies, baseline data was collected at home with trained interviewers and with the use of paper and pencil questionnaires. The self-report on behaviour was obtained 6 months (study 1) and between 8 and 9 months (study 2) after baseline data collection. In study 1, for smokers, perceived behavioural control, attitudes and subjective norm were explaining intention, whereas perceived behavioural control and habit were the most important predictors of behaviour. In study 2, smoker's intentions was mainly under the influence of perceived behavioural control and attitude, whereas behaviour was predicted by perceived behavioural control only. The present studies suggest that promotional programmes should help smokers to know and develop their will-power regarding non-smoking of cigarettes and should be informed of the effort required in order to modify smoking behaviour.

Efferent connections of the centromedian and parafascicular thalamic nuclei in the squirrel monkey: a light and electron microscopic study of the thalamostriatal projection in relation to striatal heterogeneity.

Abstract: The organization of the thalamostriatal projections arising from the centromedian (CM) and parafascicular (Pf) thalamic nuclei in the squirrel monkey (Saimiri sciureus) was studied at both light and electron microscopic levels. Following selective injections of the anterograde axonal tracer Phaseolus vulgaris-leucoagglutinin (PHA-L) into the CM or Pf, patterns of terminal arborization within the striatum were compared to the biochemical heterogeneity of the striatum as revealed by immunohistochemical staining for the calcium-binding protein calbindin D-28k (CaBP), and histochemical staining for the enzymes acetylcholinesterase (AChE) and nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-diaphorase). The PHA-L-labeled axon terminals within the striatum were further analyzed at the ultrastructural level to characterize their pattern of synaptic organization. Dense and heterogeneous terminal fields occur in the „sensorimotor” territory of the striatum after CM injections, or in the „associative” striatal territory following Pf injections. In the associative territory labeled axons arborize in a diffuse manner predominantly within areas enriched with CaBP, AChE, or NADPH-diaphorase, representing the matrix compartment, and tend to avoid areas poor in these substances, corresponding to the patch/striosome compartment. In the sensorimotor territory labeled axons form bands that occupy a subregion of the NADPH-diaphorase-rich zone in the putamen. The terminal pattern of the CM-striatal projection suggests the existence of a more complex mosaic organization within the sensorimotor territory. Ultrastructural analysis of PHA-L-labeled elements within the striatum reveals that both CM and Pf projections form asymmetric synapses upon dendrites and spines of striatal cells. A total of 339 PHA-L-labeled boutons were examined after CM injections and compared to 293 boutons following Pf injections. After CM injections, 29% of PHA-L-labeled terminals form synapses on dendritic spines and 66% on dendritic shafts, whereas after Pf injections only 12% of synapses occur on dendritic spines compared to 81% on dendritic shafts. Labeled terminals forming axosomatic or axoaxonic synapses were not seen within the striatum following either CM or Pf injections. It is concluded that in the squirrel monkey: (1) Pf-striatal fibers profusely arborize within the matrix compartment of the associative territory, (2) CM-striatal fibers form bands that occupy a subregion of the NADPH-diaphorase-rich zone within the sensorimotor territory, and (3) that both Pf- and CM-striatal projections establish asymmetric synapses with dendrites and spines of medium-sized spiny cells. These results suggest that the complementary CM and Pf projections to the striatum are in a crucial position to exert a powerful and highly ordered excitatory influence upon the output neurons of the striatum in primates.

Algae and waste water

Abstract: Microalgal cultures offer an interesting alternative for waste water treatment (urban, industrial or agricultural effluents) because they provide a tertiary biotreatment coupled with the production of potentially valuable biomass, which can be used for several purposes. We review the main abiotic, biotic and operative factors playing a role in the cultivation of microalgae. Various types of bioreactors are scrutinized keeping in view that the main limitation upon the type of usable bioreactors is the enormous volume of water to be treated. The choice of suitable microalgae and cyanobacteria is examined in terms of productivity and easiness of harvesting. The possible alternatives to harvesting are also reviewed with an emphasis on immobilized systems. Finally, the need for more research and development is discussed.

Human myoblast transplantation: Preliminary results of 4 cases

Abstract: Myoblasts from immunocompatible donors have been transplanted into the muscles (tibialis anterior, biceps brachii, and/or extensor carpi radialis longus) of 4 Duchenne patients in the advanced stages of the disease. Although no immunosuppressive treatment was used, none of the patients showed any clinical signs of rejection such as fever, redness, and inflammation. One patient transiently produced antibodies against the donor myoblasts as determined by cytofluorometric analysis. This patient and 2 others were shown to form antibodies against their donor's myotubes. Muscle biopsies of the injected tibialis anterior of 4 patients revealed that 80%, 75%, 25%, and 0% of the muscle fibers, respectively, showed some degree of dystrophin immunostaining. The contralateral noninjected muscles of the latter 3 patients did not contain any dystrophin positive fibers, while that of the first patient showed dystrophin expression in 16% of the fibers examined. Myoblasts were also injected into the extensor carpi radialis longus or the biceps brachii of these patients. A few months subsequent to injection, one patient was shown to have a 143% increase of strength during static wrist extension. This result must be interpreted with caution because a double-blind strength-measuring protocol was not used. Furthermore, we have noted that this change slowly decayed over time. The strength of 2 other patients was increased less remarkably (41% and 51%), while the strength of the fourth patient was unchanged.

Electrophysiology of a slow (0.5-4 Hz) intrinsic oscillation of cat thalamocortical neurones in vivo.

Abstract: 1. Electrophysiologically identified thalamocortical neurones have been intra- and extracellularly recorded in acutely prepared cats, under different anaesthetic conditions. 2. A slow (0.5-4 Hz) membrane potential oscillation was observed in thalamocortical cells recorded in motor, sensory, associational and intralaminar thalamic nuclei. The oscillation consisted of rhythmic low-threshold spikes alternating with after-hyperpolarizations. 3. About 80% of the neurones with intact cortical connections were set into the slow oscillatory mode by bringing their membrane potential to between -68 and -90 mV. The oscillation did not depend upon the occurrence of fast action potentials and did not outlast the imposed hyperpolarization. 4. Anatomical or functional disconnection from related cortical areas resulted in a membrane potential hyperpolarization of about 9 mV and in the occurrence of spontaneous slow oscillations in virtually all recorded neurones. The intrinsic nature of the phenomenon was supported by the lack of rhythmic postsynaptic potentials as the cells were prevented from oscillating by outward current injection. 5. In contrast with other thalamic nuclei, the slow oscillation has not been observed in anterior thalamic neurones despite their having similar basic electrophysiological properties. 6. Barbiturate administration suppressed the slow oscillatory mode, an effect accompanied by a decrease in the membrane input resistance. 7. Multiunit recordings of spontaneously oscillating cells showed epochs characterized by phase-related firing. This synchronous discharge was paralleled by a clear-cut build-up of field potentials in the frequency range of electroencephalogram slow or delta waves. 8. These results demonstrate that the majority of thalamocortical neurones are endowed with electrophysiological properties allowing them to oscillate at 0.5-4 Hz, if they have a membrane potential more negative than -65 mV and a high input resistance. Such a condition is physiologically achieved in the deepest stages of electroencephalogram-synchronized sleep, as a result of brain stem-thalamic as well as cortico-thalamic deafferentation. We postulate a thalamic contribution in the genesis of electroencephalogram delta waves during slow wave sleep, once independently oscillating thalamocortical cells become in phase.

Photonic band gaps in two-dimensional square and hexagonal lattices.

Abstract: Two-dimensional square and hexagonal lattices exhibit photonic band gaps common to s- and p-polarized waves. These gaps occur from an overlap of the gaps between the first and second p bands and higher s bands. A dielectric structure with a hexagonal lattice of air holes requires a lower index contrast to generate a band gap and gives rise to larger gaps than a square lattice. Furthermore, square and hexagonal lattices of dielectric rods in air do not give rise to band gaps even when asymmetry is introduced to lift the degeneracies.

A Prosocial Scale for the Preschool Behaviour Questionnaire: Concurrent and Predictive Correlates

Abstract: The Preschool Behaviour Questionnaire has been used widely to assess children's aggressive, anxious, and hyperactive behaviour. Items from the Prosocial Behaviour Questionnaire were added to create a prosocial scale. The resulting questionnaire was administered to teachers of three large samples of kindergarten children and shown to have three stable, orthogonal components disruptive (13 items): anxious (6 items); and prosocial (10 items). Mother and peer assessments of children were used to investigate concurrent and predictive validity. Concurrent data showed that the disruptive component was highly correlated with peer assessments and moderately correlated with mother assessments; the prosocial component was moderately correlated with peer assessments but marginally correlated with mother assessments, whereas the anxious component was marginally correlated with peer assessments and moderately correlated with mother assessments. From a predictive perspective it was shown that highly disruptive boys in k...

Ecology of sea ice biota - 1. Habitat, terminology, and methodology

Abstract: Polar regions are covered by extensive sea ice that is inhabited by a variety of plants and animals. The environments where the organisms live vary depending on the structure and age of the ice. Many terms have been used to describe the habitats and the organisms. We here characterize the habitats and communities and suggest some standard terms for them. We also suggest routine sampling methods and reporting units for measurements of biological and chemical variables. © 1992 Springer-Verlag GmbH & Co. KG.

Congenital adrenal hyperplasia due to point mutations in the type II 3 beta-hydroxysteroid dehydrogenase gene.

Abstract: Classical 3β–hydroxysteroid dehydrogenase /Δ5–Δ4–isomerase (3β–HSD) deficiency is an autosomal recessive form of congenital adrenal hyperplasia characterized by a severe impairment of steroid biosynthesis in both the adrenals and the gonads We describe the nucleotide sequence of the two highly homologous genes encoding 3β–HSD isoenzymes in three classic 3β–HSD deficient patients belonging to two apparently unrelated pedigrees No mutation was detected in the type I 3β–HSD gene, which is mainly expressed in the placenta and peripheral tissues Both nonsense and frameshift mutations, however, were found in the type II 3β–HSD gene, which is the predominant 3β–HSD gene expressed in the adrenals and gonads, thus providing the first elucidation of the molecular basis of this disorder

Psychological distress after initial treatment of breast cancer. Assessment of potential risk factors.

Abstract: Background. Patient and disease characteristics are often mentioned by clinicians as possible risk factors for psychological distress among women with breast cancer. However, either these factors have not been evaluated or when they were evaluated, results were inconclusive. Methods. Potential risk factors for psychological distress were assessed among 205 patients with newly diagnosed breast cancer by home interview 3 and 18 months after surgery. Results. At 3 months, proportions of women with high distress reporting 0-1, 2-3, 4-5, and 6-15 stressful life events in the 5 years preceding diagnosis were 17%, 20%, 28%, and 37%, respectively (P = 0.006). High levels of psychological distress were present in 63.1% of women with a history of depression, compared with 14.3% of those with no such history (P = 0.000). Associations of these factors with distress also were present 18 months after diagnosis. At 18 months only, distress was more frequent in women with regional disease (44%) than in those with localized disease (22%) (P = 0.006). Age, education, and marital status had little or no association with levels of psychological distress. Conclusions. Number of stressful life events before diagnosis and history of depression appear to be strong indicators of the risk of psychological distress and may be useful for identifying patients with breast cancer in need of more intense psychosocial support.

Bitter flavour in dairy products. II. A review of bitter peptides from caseins: their formation, isolation and identification structure masking and inhibition

Abstract: HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. Bitter flavour in dairy products. II. A review of bitter peptides from caseins: their formation, isolation and identification, structure masking and inhibition L Lemieux, Re Simard

Prevention of deep vein thrombosis after major knee surgery--a randomized, double-blind trial comparing a low molecular weight heparin fragment (enoxaparin) to placebo.

Abstract: Consecutive patients undergoing knee arthroplasty or tibial osteotomy at four participating hospitals received either enoxaparin, 30 mg subcutaneously every 12 h (n = 66) or an identical-appearing placebo (n = 65). All study medications started the morning after the operation and were continued up to a maximum of 14 days. Patients underwent surveillance with 125I-fibrinogen leg scanning and impedance plethysmography. Bilateral contrast venography was performed routinely at Day 14 or at time of discharge, if sooner. Deep vein thrombosis was detected by venography in 35 of 54 patients (65%) in the placebo group and in 8 of 41 patients in the enoxaparin group (19%), a risk reduction of 71%, P less than 0.0001. For the entire study group, deep vein thrombosis was detected by either venography of non-invasive tests in 37 of 64 patients (58%) in the placebo group and in 11 of 65 patients (17%) in the enoxaparin group, a risk reduction of 71%, P less than 0.0001. Proximal vein thrombosis was found in 19% of the placebo patients and in none of the enoxaparin patients, a risk reduction of 100%, P less than 0.001. Bleeding complications occurred in 5 of 65 patients (8%) in the placebo group and in 4 of 66 patients (6%) in the enoxaparin group, P = 0.71. There were no differences in the amount of blood loss, minimum hemoglobin levels and number of units of packed red cells given between the two treatment groups. We conclude that a fixed dose regimen of enoxaparin, started post-operatively, is an effective and safe regimen for reducing the frequency of deep vein thrombosis after major knee surgery.

Mapping of an idiosyncratic schema

Abstract: Among researchers interested in organizations and management, some of those who use cognitive mapping share a common objective: to improve organizational action. Some intervene directly at the level of the organization while others prefer to achieve this indirectly, by working at the individual level. Nevertheless those who work at the individual level rely on the ‘emancipatory’properties of a cognitive map, which facilitates reflectiveness. After calling upon the notions of natural logic, schematization, contextuality, representation, knowledge and schema to characterize the cognitive map and its construction, we present a case, that of the idiosyncratic map of the owner-manager of a small business. We describe the mode of construction of the map and its content. A critical discussion follows underlining the traps to avoid, the elements to be improved and those that should be kept for construction of future idiosyncratic maps.

Life cycle of glomus intraradix in root organ culture

Abstract: The entire vegetative life cycle of the vesicular-arbuscular mycorrhizal fungus Glomus intraradix was followed in a simple monoxenic culture system using Ri T DNA-transformed carrot roots and nontransformed tomato roots as plant partners. Fungal development, from the growth of initial germ tubes to the formation of an external mycelium network and spore production, was observed nondestructively using light microscopy. Surface-sterilized spores isolated from pot culture constituted an excellent source of fungal inoculum. These spores germinated readily on the nutrient medium and only a low rate of contamination was recorded. Germ tubes approaching the surface of isolated roots changed their growth pattern and branched profusely in response to root factors. Throughout the growth process it was possible to observe directly the formation of terminal and intercalary secondary spores, numerous hyphal anastomoses and arbuscle-like structures, intracellular vesicles and spores. The extent of internal root colonization by G. intraradix was relatively limited, but it was sufficient to permit the in vitro formation of hundreds of new spores free of contaminants, which were viable and capable of colonizing host roots.